The broad, long-term objective of this research project is to improve the design, access, and use of networked electronic health information resources on the Internet through increased understanding of these emerging new phenomena. The specific aims of the project contribute to that object by providing detailed description, a "natural history," of Internet health information resources and their use by experienced Internet searchers. Information in the health domain, as in other domains, is in the throes of an historic shift from a print base to an electronic base. The characteristics of the shift and the adaptation of the health domain to new electronic forms of recorded knowledge will be essential for health care, education and research in the upcoming decades and beyond. The specific aims of the project are described below, each embodied in a separate study within the total project: 1. Conduct a baseline study of the characteristics of health information resources on the Internet, and repeat the study after one year.